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Search engines expose vulnerabilities

Malicious hackers use search engines to parse through a Web site's source code

By Mark Willoughby
July 29, 2004 12:00 PM ET

Computerworld - Internet search engines have long been used in uncovering vulnerabilities for launching attacks, and security experts expect malicious hackers to increase their use of the technology to find exploitable information.
Hackers have long used search engines to parse through a Web site's source code, seeking clues about what the site contains and configuration information that may be useful in launching an attack.
"People have discovered that they can make a really tight Google query that comes back with results that show lots of vulnerabilities at once," said Matt Fisher, an application security analyst at SPI Dynamics Inc. in Atlanta. "The hackers are getting a bunch of potential targets with one Web search."
Fisher said past software development practices for Web sites often resulted in insecure code containing critical information. Hackers, using a Web browser and a search engine, frequently parse Web sites looking for just such exposed nuggets of exploitable information. As examples, Fisher cited backup files and source code stored in clear text or as HTML files, embedded comments containing passwords and database schemas.
"Any invalid file extension, or a file ending in .inc, .bak or .old, will get source code," Fisher said. "The issue is poor Web application security" and doesn't reflect on search engine security practices, he added. "Developers are not taught secure coding. They're taught functional and efficient coding, but not security. There's simply a lack of awareness."
Web application vulnerabilities are not homogeneous, and every Web site is unique, Fisher said. "You can't issue a patch for a Web application vulnerability. You've got to fix it yourself, and since Port 80 must be open, firewalls won't protect this type of vulnerability."
Google Inc. spokesman Nate Tyler declined to comment, citing the silent period required by the Securities and Exchange Commission before the search engine company's pending initial public offering. Spokesmen for Lycos Inc. and Yahoo Inc. didn't return calls.
Hackers have compounded the problem by using search engines to conceal their locations and complicate forensics, said Chris Wysopal, vice president of engineering at security assessment company @stake Inc. in Cambridge, Mass.
"When you search for a particular vulnerability using a search engine, the search engine pulls all the [targeted] files into the search engine cache, which doesn't leave the hacker's IP address, so it covers their tracks," Wysopal said. White hat ethical hackers conducting penetration tests and security assessments also commonly use search engines, he said.
The recent MyDoom.O worm used search engines to find more e-mail addresses in targeted domains (see story). Search engines would have to remove functionality to try to thwart



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